1. Field of the Invention
The present invention relates generally to the field of road construction apparatus and, more particularly, but not by way of limitation, to road construction apparatus using a planar apparatus for removing a top portion of an existing roadway.
2. Description of the Prior Art
In the repair and maintenance of paved roads, a planar apparatus of the type described in the related U.S. patent application Ser. No. 672,326, entitled "A Method and Apparatus for Planing a Paved Roadway", assigned to the assignee of the present invention, is finding increasing usage. A planar apparatus of this type comprises a rotating drum planer cutter having cutting teeth which are disposed to engage the top portion of an existing roadway as the planar cutter is caused to move therealong. Not only has this planar apparatus afforded a means for effecting a new surface that has a predetermined grade and cross-slope, the material that is removed from the roadway is reusable as a part of newly prepared hotmix asphalt that is used to form a new roadway layer on top of the new surface created by the planer apparatus.
It has been found that the use of a planer apparatus of the type mentioned often results in cuttings that are not uniform or predictable in size for the reason that the planer apparatus often tends to remove the top portion of the roadway in large chunks, especially near the upper surface thereof. In order to meet the requirement of size and uniformity required of aggregate used to form new hotmix asphalt, the removed cuttings must be broken apart by appropriate means and graded before being recycled as a constituent portion of new paving material.
Not only must energy be expended to size the cuttings, but the cuttings must be collected and passed through a sizing and grading operation after the planing operation, which represents a loss of economy as this is an additional material handling step. It would be desirable if the cuttings could be removed from the roadway having an acceptable particulate size range. In this form, the cuttings could be conveyed directly to a hotmix asphalt mixing machine or the like, melted down and mixed with new paving material, and deposited on the newly created surface to form a new roadway surface. In this way, the removed roadway material would be recycled directly, eliminating additional sizing and grading operations, and combined in a predetermined mixture with new roadway paving material. Further, this would permit the lay down of the new roadway layer by machinery that follows immediately behind the planer apparatus.